hugh thomas, technical authority for process engineering
TRANSCRIPT
W W T W AT E R Q U A L I T Y C O N F E R E N C E
Hugh Thomas, Technical Authority for Process Engineering
8th November 2018
W H AT D O E S R E S I L I E N C E L O O K L I K E ?
Reducing the risk of supply interruptions
Allowing asset outages
Moving raw or treated water to abstraction constrained areas
Allowing blending and reducing need for new treatment
works
The industry is moving towards greater integration of networks and sources
RAW WATER SOURCE
SERVICE RESERVOIRS
WATER TREATMENT WORKS
TRUNK MAINS
DISTRIBUTION NETWORK
CUSTOMERS
S O W H E R E A R E W E M A N A G I N G W Q R I S K S ?
…AT EVERY STEP OF THE WATER SUPPLY SYSTEM !
Stakeholder
consultation
Policy setting
Enhanced control
measures
selected and
designed
Control points
and new control
measures
implemented
Procedures and
manuals aligned
with risks and
control points
Structured risk-
based study –
HACCP / HAZOP
Monitor, review and revise
WAT E R Q U A L I T Y C E N T R E D
Data driven
source risk
assessment
Raw water storage can lead to:
Algal blooms
Taste & odour or toxic
by-products
Soluble metals
Source water quality
management includes:
Mixing
Aeration
Other active and passive
measures
New sources and
catchment risks
Catchment management
Planned effluent re-use
CIP findings
S O U R C E WAT E R Q U A L I T Y: U N D E R S TA N D A N D M A N A G E R I S K S
WAT E R T R E AT M E N T
Atkins are specialists in all conventional and advanced water treatment processes.
We support clients at all stages of design – from concept / strategic planning to detailed
design, delivery and optimisation.
We’re focused on water quality – compliance and customer
acceptability, including parameters such as:
Iron and manganese
Taste and odour
Disinfectionby-products
Disinfection and cryptosporidium
25
Manganese54.938
Mn Fe26
Iron55.845
Assess water quality risks
Understand WQ trends using AQWA
Process selection using in-house modelling tools
Size and performance of selected processes
Cost and carbon estimating
Identify most sustainable, best value solutions that manage the business risks
S T R AT E G I C P L A N N I N G – I D E N T I F Y I N G T H E R I G H T L O N G - T E R M S O L U T I O N
OPEXspend ML
Labour,£12.3
Chemicals, £32.4Sludge Disposal,£1.0
Power, £39.9
Phosphoric Acid,£2.5
Sulphuric Acid,£1.4
Sulphuric Acid (for raw water pH correction), £0.4
Sulphur Dioxide,£1.4
Sodium Hypochlorite,£3.0
Polydadmac,£1.3
Polyelectrolyte (dewatering), £1.1
Polyaluminium Chloride, £11.4
Caustic Soda,£9.8
10/08/2010
2
1.8
1.6
1.4
1.2
0.8
0.6
0.4
0.2
0
1
23/12/2011 18/09/2014 31/01/201606/05/2013
Date
TO
C(m
g/L
)
D E TA I L E D D E S I G N S D E V E L O P E D A N D R E V I E W E D I N B I M C O M P L I A N T E N V I R O N M E N T
BIM compliant design offers
many downstream opportunities:
Safer, more accurate design &
safety reviews
More efficient construction
Ddigital asset management
VR based Ooperator training
and improved human factor
design
Future changes fully integrated
– no ‘out of date’
documentation
Wessex Water Integrated
Supply Grid
Optimiser maintaining water
quality and facilitating PODDS
conditioning.
Chloramination/chlorination
T R U N K M A I N S A N D B U L K WAT E R T R A N S F E R
Preventing water quality deteriorating
Don’t introduce new risks to customers
STWL Birmingham Resilience
Project
Operational Readiness WQMP
– all risks managed (compliance
and customer acceptability)
including corrosivity
UU West Cumbria
Customer acceptability –
chlorine T&O
W E S S E X WAT E R G R I D – O P T I M I S E R
Standa one sources
Low f ow source
itrate and standa ine
Area of su demand deficit
Water su andsewera e ser ices area
Sewera e ser ices on
Water su ser ices
E istin network stora e tanksand um in stations
Pro osed i e ines stora e tanksand um in stations
Sources at risk ofe ceedin nitrate imits
Taunton
rid ewater
risto
at
i en am
Sa is ur
S aftes ur
Yeo i andfordForum
Dorc ester
ournemout
R STOL HA EL
E L SH HA EL
S ine main
East West ink
Poo e
S E V E R N T R E N T B I R M I N G H A M R E S I L I E N C E : M A N A G I N G WAT E R Q U A L I T Y R I S K S
Major change of source water – upland reservoir to lowland river:
Soft to hard water and back again – change to 1.3 million customers!
Atkins took an industry leading approach to water quality management:
developed a plan (WQMP) to quantify and mitigate all DWSP risks including:
Customer engagementon acceptability: hardness, T&O, chlorine residual
Lead and iron compliance– extensive corrosion trials
on sources andchangeover
Discoloured water:Mains conditioning
Nitrate:blending modelling
Pesticides: treatment and
monitoring
Potential pathways for
surface water ingress
Sometimes over-sized
Non-ideal hydraulic designs
lead to quiescent areas with
high water age
Deposition of sediment
creates a risk if level drawn
right down
Portsmouth Water
Risk assessment of all
reservoirs – water quality and
free chlorine residual
High risk reservoirs taken
forward to CFD modelling
These CFD models can be
used to test hydraulic
interventions
S E R V I C E R E S E R V O I R S
Solution Time 22.11 (s)
D I S T R I B U T I O N N E T W O R K
Current SetupAdjustedProposed Setup
Secondary Dosing
UU west Cumbria: chlorine decay modelling
Customer acceptability (taste & odour) and microbiological compliance
WAT E R Q U A L I T Y D E T E R I O R AT I O N
Getting water quality right at the WTW is only part of the story.
Failures at the tap are far more significant.
FAILURES OF STANDARDS IN
ENGLAND 2017
MICROBIOLOGICAL TESTS:
The number of tests performed and the number of tests not
meeting the standard.
Parameter Current
Standard
Total number
of tests
Number of tests not
meeting the standard
Additional
information
Water leaving water treatment works
E.coli 0/100ml 154,431 1 SVT (1)
Coliform bacteria 0/100ml 154,430 40 AFW (2), ANH (4), NNE (1),
SBW (1), SEW (5), SRN (5),
SST (3), SVT (9), SWT (1)
TMS (5), UUT (1), WSX (1),
YKS (2)
Clostridium
perfringens 0/100ml 41,989 17ANH (1), ESK (2), NNE (1),
SBW (1), SRN (1), SVT (1),
SWT (I), TMS (2), UUT (1),
YKS (6)
Turbidity1 1NTU 148,501 33 AFW (2), ANH (1), CAM (2),
ESK (1), NNE (9), SES (1),
SEW (1), SVT (1), TMS (6),
UUT (1) WSX (14) YKS (4)
Water leaving service reservoirs
E.coli 0/100ml 186,163 11 AFW (1), BRL (1), NNE (2),
SEW (1), SRN (1), SVT (1),
SWT (1), UUT (1), YKS (2)
Coliform bacteria0/100ml in 95% of
tests at each reservoir 186,163 120
AFW (11), ANH (7), BRL
(2), CAM (1), ESK (2), NNE
(6), SBW (2), SEW (11),
SRN (6), SVT (26), SWT
(8), TMS (11), UUT (6),
WSX (5), YKS (18)
2 reservoirs from a total of
3,689 did not meet the
annual 95% compliance
rule; Jacks Hill Reservoir
(AFW), and Harebell,
reservoir 3 West (AFW)
Water sampled at consumers’ taps
E.coli 0/100ml 143,628 26 AFW (2), ANH (2), BRL (1),
ESK (5), SRN (1), SST (1)
SVT (4), SWT (1) TMS (4),
UUT (2) YKS (3)
Enterococci 0/100ml 11,508 4 SSE (1), SWT (1), TMS (1).
UUT (I)
1 Turbidity is a critical control parameter for water treatment and disinfection
Figures include all failures of
EU and national standards
taken at treatment works,
service reservoirs amd taps.
T e cate or ‘ot er’ inc udes
Total pesticides (1),
Trihalomethanes (1), Nitrite
(1), Nitrite/Nitrate formula (10),
PAH (2), Copper (3), Turbidity
(3), Enterococci (4)
160
138
70
69
38
36
30
1613 7 16
Coliform bacteria Taste and odour
Iron Lead
Pesticides E.coli
Nickel Manganese
Aluminium Benxo(a)pyrene
Other
THANK YOU FOR L ISTENING
For more information, get in touch:
Hugh Thomas, Chief Engineer
+44 1454 66 3294